strlcpy.c

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/*      $OpenBSD: strlcpy.c,v 1.9 2019/01/25 00:19:26 millert Exp $    */

/*
 * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Copy string src to buffer dst of size dsize.  At most dsize-1
 * chars will be copied.  Always NUL terminates (unless dsize == 0).
 * Returns strlen(src); if retval >= dsize, truncation occurred.
 */

#include "compat.h"

#ifndef HAVE_STRLCPY
size_t strlcpy(char *dst, const char *src, size_t dsize)
{
    const char *osrc = src;
    size_t nleft = dsize;

    /* Copy as many bytes as will fit. */
    if (nleft != 0) {
        while (--nleft != 0) {
            if ((*dst++ = *src++) == '\0')
                break;
        }
    }

    /* Not enough room in dst, add NUL and traverse rest of src. */
    if (nleft == 0) {
        if (dsize != 0)
            *dst = '\0';        /* NUL-terminate dst */
        while (*src++)
            ;
    }

    return(src - osrc - 1);    /* count does not include NUL */
}
#endif